Software Support

Calxeda supports Ubuntu and Fedora, though any distribution based on the (32-bit) ARM Linux kernel should in theory be able to run on the EnergyCore SoCs. As for availability, there are already prebuilt Highbank kernel images available in the Ubuntu ARM repository and Calxeda has set up a PPA of its own to ease its kernel development.

The company has also joined Linaro—the non-profit organization aiming to bring the open source ecosystem to ARM SoCs.

The ARM Server CPU

A dual Xeon E5 or Opteron 6300 server has much more processing power than most of us need to run one server application. That is the reason why it is not uncommon to see 10, 20 or even more virtual machines running on top of them. Extremely large databases and HPC applications are the noticeable exceptions, but in general, server purchasers are rarely worried about whether or not the new server will be fast enough to run one application.

Returning to our Boston Viridis server, the whole idea behind the server is not to virtualize but to give each server application its own physical node. Each server node has one quad-core Cortex-A9 with 4MB of L2 cache and 4GB of RAM. With that being the case, the question "what can this server node cope with?" is a lot more relevant. We will show you a real world load further in this review, but we thought it would be good to first characterize the performance profile of the EnergyCore-1000 at 1.4GHz. We used four different benchmarks: Stream, 7z LZMA compression, 7z LZMA decompression, and make/gcc building and compiling.

We compare the ECX-1000 (quad-core, 3.8~5W, 40nm) with an Intel Atom 230 (1.6GHz single-core plus Hyper-Threading, 4W TDP, 45nm), Atom N450 (1.66GHz single-core + HTT, 5.5W TDP, 45nm), Atom N2800 (1.86GHz dual-core + HTT, 6.5W, 32nm), and an Intel Xeon E5-2650L (1.8-2.3GHz octal-core, 70W TDP, 32nm).

The best comparable Atom would be the Atom S1200, which is Intel's first micro-server chip. However the latter was not available to us yet, but we are actively trying to get Intel's latest Atom in house for testing. We will update our numbers as soon as we can get an Atom S1200 system. The Atom N2800 should be very close to the S1200, as it has the same architecture, L2 cache size, TDP, and runs at similar clockspeeds. The Atom N2800 supports DDR3-1066 while Centerton will support DDR3-1333, but we have reason to believe (see further) that this won't matter.

The Atom 230/330 and N450 are old 45nm chips (2008-2010). And before you think using the Atom 230 and N450 is useless: the Atom architecture has not changed for years. Intel has lowered the power consumption, increased the clockspeed, and integrated a (slightly) faster memory controller, but essentially the Atom 230 has the same core as the latest Atom N2000. I quote Anand as he puts it succinctly: "Atom is in dire need of an architecture update (something we'll get in 2013)."

So for now, the Atom 230 and N450 numbers give us a good way to evaluate how the improvements in the "uncore" impact server performance. It is also interesting to see where the ECX-1000 lands. Does it outperform the N2800, or is just barely above the older Atom cores?


A Closer Look at the Server Node Benchmarking Configuration
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  • tuxRoller - Tuesday, March 12, 2013 - link

    Why WOULD you expect DVFS to boost performance?
    You seem to think it slightly revelational that the scores are slightly lower (but perhaps statistically meaningless).
  • dig23 - Tuesday, March 12, 2013 - link

    On-demand seems fair choice to me, its what best you can do on this OSes. But I will be very interested to see energy efficiency numbers when DVFS working on swarm of ARM nodes...:)
  • tuxRoller - Tuesday, March 12, 2013 - link

    It's not cpu governor I'm talking about but DVFS in particular.
    There's bound to be some small amount of latency involved with the process.
    It's point isn't for best performance but energy efficiency thus why I made the comment in the first place.
  • JarredWalton - Tuesday, March 12, 2013 - link

    There's the potential for DVFS to optimize for better performance on a few cores while putting some of the other cores into a lower P-state, but I think that would be more for stuff like Turbo Boost/Turbo Core. It's also possible Johan is referring to the potential for the optimizations to simply improve performance in general.
  • CodyHall - Friday, March 15, 2013 - link

    Love my job, since I've been bringing in $5600… I sit at home, music playing while I work in front of my new iMac that I got now that I'm making it online.(Click Home information)
  • JohanAnandtech - Wednesday, March 13, 2013 - link

    Can you tell me where I got you confused? Because I write "This allowed us to make use of Dynamic Voltage and Frequency Scaling (DVFS, P-states) using the CPUfreq tool. First let's see if all these power saving tweaks have reduced the total throughput."

    So it should been clear that we are looking for a better performance/watt ratio. The interesting thing to note is that ARM benefits from p-states, and that Intel's excellent implementation of C-states makes p-states almost useless.
  • Twonky - Wednesday, March 13, 2013 - link

    For information about a year ago the following post on the Linkedin ARM Based Group gave a link to a M.Sc. thesis publishing figures on the performance/watt ratio for Cortex-A8 and Cortex-A9 based boards:
  • AncientWisdom - Tuesday, March 12, 2013 - link

    Very interesting read, thanks!
  • staiaoman - Tuesday, March 12, 2013 - link

    Damn, Johan. As always- an incredible writeup. Interesting thought experiment to figure that an upper bound on damage to INTC server share might be found by simply looking at how much of the market is running applications like your web server here (where single-threaded performance isn't as important).

    Intel powering phones and ARM chips in servers...the end is nigh.
  • JohanAnandtech - Thursday, March 14, 2013 - link

    Thanks Staiaoman :-). I'll leave the though experiment to you :-)

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